English

The Inverse Monoid of Partial Inner Automorphisms of a Semigroup

Group Theory 2026-05-04 v1

Abstract

We introduce the inverse monoid of inner partial automorphisms of a semigroup -- a tool that associates to every semigroup an inverse semigroup. When the semigroup is a group, this inverse semigroup is isomorphic to the group of inner automorphisms with a zero adjoined. We then describe this structure for completely simple semigroups, the full transformation monoid, and the endomorphism monoid of a finite GG-set when GG is a finite abelian group. The paper ends with some open problems.

Keywords

Cite

@article{arxiv.2605.00041,
  title  = {The Inverse Monoid of Partial Inner Automorphisms of a Semigroup},
  author = {João Araújo and Wolfram Bentz and Michael Kinyon and Janusz Konieczny António Malheiro and Valentin Mercier},
  journal= {arXiv preprint arXiv:2605.00041},
  year   = {2026}
}

Comments

This paper was originally section 5 of arXiv:2301.04252 . We spun it off into its own paper at the suggestion of the referee. If the arXiv system flags it for substantial text overlap, that's why. arXiv admin note: substantial text overlap with arXiv:2301.04252